Process of fumigating



Patented Nov. 3, i925. it

1 f LSSQMZ PATENT @FFHCEQ i I I WALTEBI S. LANDIS, OE WHITESTONE LANDING, NEW YORK, AND GUY H. BUCHANAN, OF WESTFIELD, NEW JERSEY, ASSIGNORS AMERICAN CYANAMID COMPANY, OF

No Drawing.

new YORK, N. Y., A oonronn'rron'or MAINE.

.rnoonss or nuiureewrne.

Application filed July 8 To all whom it may concern:

. and GUY H. BUCHANAN, both citizens of the United States, respectively, residing at \Vhitestone Landing, in the county of Queens, State of New York, and \Vestfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Processes of Fumigating; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertain's' to make and use th same. y

This invention relates to a process of fumigating with highly poisonous fumigants, and has for its object to improve certain of the processes heretofore proposedand now in wide use, to the end that they may be made more efficient and less dangerous than they are as at present practiced. With these and other objects in view, the invention consists in the novel steps and combinations of steps'constitutingthe process, all as will be more fully disclosed below and particularly pointed out in the claims. In order that the present invention may be the more clearly understood, it is said:

In the fumigation of buildings, shipsand other enclosed spaces with hydrocyanic acid gas for the purpose of destroying vermin and other pests, the .common practice has been to determine thevolume of the space to be fumigatedand then to atomizeor vaporize into this space a suitable quantity of hydrocyanic acid.

The enclosed space, 'charged with the fumigant, is permitted to stand closed for a suitable. length of time, usually one or two hours, or even longer, in the case of certain special work, and is then opened up and the poisonous fuinigant displaced by admission of fresh air from the outside. iVhere suitable means of ventilating the enclosed space are at hand, the dissipation of the poisonous fumes is not a difficult problem, but in the case of ships and warehouses from five to twelve'hours are usually required to efiectuallyremove the poisonous gas and render the space habitable. The long time necessary for clearing out the hydrocyanic acid fumes where facilities for ventilation are 1921. Serial No. 483,262,

limited,is at times asource of considerable, expense In the case ofacargo car ing steamship for example, it may mean a: clay in unloading or re-loading of the ship and a very considerable demurrage charge may accrue due to this tie-up of the vessel.

On the other hand, we-have found a simple and expedient method of destroying the residual hydrocyanic acid so as to eliminate it in a' comparatively short time, thereby gaining. the use of the space to be 'fuinigated much more quickly. x p

In carrying out the present procedure, we admit to the space'after fumigating, a volatile'aldehyde and ammonia. Aldehyde Va por, such as, for example, from acetalde' hyde, reacts only very slowly vvwith the dilute gaseous hydrocyanic acid, but in the presence of a third material, such as ammonia for example, the reaction of the three products takes .place' very rapidly and is remarkably complete. For eXamp'le,.-in carrying out this process we close up the space to be fumigated comparatively tight, and introduce into this space suflicient hydrocyanic. acid for effective fumigation.

tity is such as to produce from 0.2 per cent up to one per cent by volume of hydrocyanic' acid gas in the space to be fumigated, and

This quan-.

the application may be made either by gen crating the gas directly in the space, or by necessary to insure killing of the pest to be eliminated, at the end of which timewe introduce for example onemolecular weight using liquid hydrocyanic acid which is ap of ammonia for each molecular Weight of V hydrocyanicacid used, and one and onefourth molecular weights of acetaldehyde to each molecular weight of hydrocyanic acidused. The ammonia-may be introduced by atomizin very strong aqua ammonia, or preferably. y direct expansion'of anhy- 'drous ammonia, while the acetaldehyde may be introduced through the same type of apparatus as is used for applying liquid liy drocyanic acid, as it is very volatile. A reaction between the three constituents takes place, and in less than one' hour it i will be found that the hydrocyanic aoid'has been destroyed and one may enter the room we prefer to use said compounds in propor t-ions of substantially more than one molecu or space that has been fumigated with comparative safety. We have found that it makes no difference whether the ammonia I or the aldehyde has been added lirst, or whether both are introduced simultaneously. Further, wehave found that one need not adhere very closely to the above proportions of ammonia and aldehyde and in many cases lar weight of ammonia to one and onefourth molecular weights of aldehyde.

I We do not know the nature of the com-' pounds formed and. from suchanalysis as we have been able to make of the products ,of'reaction collected in a closed space, we

have been unable to identify the resulting product with any of the catalogued organic compounds which one would expect. It IS apparent that in the extremely Idilute state and using anhydrous material,'- a new and complex reaction takes place producing new results. WVe have also noticed that chang ing the proportions of the various reagents seems to have a marked eflect upon the char- .acter of the products formed, but in no case.

have we been able to identify the result. It is entirely different from that obtained by mixing these three ingredients together in more or less concentrated form in solution. I The reactions between anhydrous hydrocyanic acid andeither the ammonia or' the.

aldehydes alone are extremely slow andwe have, therefore, found that it is possible to introduce either the ammonia or the aldehyde alon with the hydrocyanic .acid with out interfering with". the fumigation and then, after fumigation is complete, we may introduce the third reagent to destroy the hydrocyanic acid. I

'Weha-ve also found that variousvolatile aldehydes may be used, all of which seemto exert this same reaction, but with ,difi'erent velocities, but We have obtained the most rapid destruction of the acid by the use of acetaldehyde.

The advantages of, this process are that we can avoid the-closing oft ofa fumigated space from use for a considerable period of' time, owing to the relatively rapid neutraliin ury through some one, inadvertant-ly enteringthe space, which has beenflfuinigated. Further, the formation of pocketsjoffumigant which are not removed in-ordinary Ventilation is avoided, because thematerials which we employ for the neutralization will eeaeea above disclosed, without departing from the spirit of the invention and therefore-we do 7 not wish to be limited to the above disclosure except as may be required by the claims.

What we claim is: r

. .1. The process of funiigating with a poisonous fumigant which consists in introducing said fumigunt into the space to be fumigated; and also introducing into said soace after the fumigating action is comp etedan agent adapted to react with said fumigant to destroy the latter, substantially as described. ,2. The process of fumigating a space wit-h a poisonous fumigant which consists in first introducing into said space a fumigant and -"tli e'n" after the 'fuinigating action is completed, introducing into said spacean agent adapted to' react with and to destroy said fumigant; and also introducing into said space-an agent adapted to accelerate the reaction between said first named agent and said funiigl-int, substantially as described. I 3. The process of fuiniga'ting with a poisonous fumigant which consists in introducgated; and subsequently introducing into said space an agent adapted t'p react relatively slowly with said fumigant to destroy the latter, together with an agent adaptedto mg said fumigantinto the space to be fumiaccelerate said reaction, substantially as de- I scribed.

l. The process of fumigatingt with a poisonous fumigant which consists in introducing said fumigant, together wi%h an agent adapted to react relatively slow y therewith to destroy said fumigant into he space to be fumigated andsubsequently \introducing' into said space an agent adapted to accelerate the reaction between said first named agent and said fumigant,,. substantially as described.

The process of fumigating with a poisonous fumigant which consists in introducing said fumigant together with an accel era-ting agent into the space to be fumigated; and subsequently introducing 6.v he process of fumigating with highly poisonousifumiga'nts"which consists in.intro zation,v which not only avoids-thedisadvan; tage of non-use of the building or other" space, but also lessens the dangerof fatal,

ducihg hydrocyanicacid gas into the space to 'be"fumigated; and. also introducing intosaid space a volatile aldehyde, adapted to react with said gas todestroy the same, and

into I said space'an ig'ent adapted to norma ly re- 'lCt relatively slowly with said fumigant to destro ,the same, substantially as described.

an accelerating agent, substantially ajs' described. I I I 7. The process of fumigating with highly poisonous fumigants which consists in introducing hydrocyanio acid gas into the space to be fumigated; and subsequently introducingrinto said spaceja volatile aldehyde hose skilled in the art adapted to react relatively 'slowly'with, said gas to destroy the same, together with a sufiicient amount of ammonia to accelerate the reaction between the saidgas .and the said aldehyde, substantially as described.

8. The process of fumigating with'highly poisonous fumigants which consists in introducing hydrocyanic acid gas together with a volatile aldehyde into the space to be fumigated; and subsequently introducing into said space a sufiicient quantity of ammonia to accelerate the reaction between the said aldehyde and the said gas, to destroy. the

.latter, substantially as described.

presence of said ammonia will react rapidly with the said gas to destroy the same, sub stantially as described.

10. The process'of 'fumiga'ting with highly poisonous fumigants which consists in introducing hydrocyanic acid gas into the space to be fumigated; and subsequently -introducing into said space ammonia and acetaldehyde to destroy the said gas, substantially Y as described.

' .11. The process of fumigating with highly poisonous fumigants which consistsin-mtroducing hydrocyanic acid gas into the space to be fumigated; and subsequently introducing into the said space ammonia and acetald'ehyde in substantially the proportions of one molecular weight of ammonia and one and one-fourth molecular weights of acetaldehyde to each molecular weight of hydrocyanic acid used, substantially as'described.

- 12. The process of fumigating wi'th highly poisonous fumigants which .consists in intro-' duci'ng hydrocyanic acid gas into the space to be fumigated and subsequently introducing into said-space ammonia and-aldehyde in the proportions of substantially more than one molecular weight of ammonia to one and one quarter molecular weights of aldehyde, substantially as described.

In testimony whereof we afiix our signatures.

WALTER S. LANDIS. GUY H. BUCHANAN. 

